P
US11587992B2ActiveUtilityPatentIndex 62

Display apparatus comprising thin film transistor

Assignee: LG DISPLAY CO LTDPriority: Dec 12, 2019Filed: Dec 9, 2020Granted: Feb 21, 2023
Est. expiryDec 12, 2039(~13.4 yrs left)· nominal 20-yr term from priority
Inventors:KIM SEUNGJINLEE SOHYUNG
H10K 50/805H10K 59/124H10K 59/1216H10K 59/80H10K 59/12H10D 30/6755H10D 30/6713H10D 86/423H10D 86/60H10D 86/471H10K 59/1213H10K 59/123H01L 29/7869H01L 27/3244H01L 29/78618
62
PatentIndex Score
0
Cited by
8
References
28
Claims

Abstract

Disclosed is a display apparatus including a first thin film transistor (TFT) and a second thin film transistor having a bottom gate structure and including an oxide semiconductor layer. The first TFT may be used as a switching device and the second TFT may be used as a driving device, and these TFTs have different operation properties from each other. One or more embodiments of the present disclosure provides a method of arranging a plurality of TFTs having different properties in a display apparatus. This not only provides a display apparatus with TFTs integrated at a high density but also an efficient way of driving the display apparatus.

Claims

exact text as granted — not AI-modified
The invention claimed is: 
     
       1. A display apparatus, comprising:
 a substrate; 
 a first gate electrode on the substrate; 
 a first active layer spaced apart from the first gate electrode and provided with at least a portion overlapping the first gate electrode; 
 a first source electrode and a first drain electrode connected with the first active layer respectively; 
 a second gate electrode connected with any one of the first source electrode or the first drain electrode; 
 a second active layer spaced apart from the second gate electrode and provided with at least a portion overlapping the second gate electrode; 
 a second source electrode and a second drain electrode connected with the second active layer respectively; 
 a display element connected with any one of the second source electrode or the second drain electrode; 
 a first capacitor electrode disposed on a same layer as that of the first gate electrode; 
 a second capacitor electrode disposed on a same layer as those of the first source electrode and the first drain electrode; and 
 a third capacitor electrode disposed on a same layer as those of the second source electrode and the second drain electrode, 
 wherein the first gate electrode is disposed between the substrate and the first active layer, 
 wherein the second gate electrode is disposed between the substrate and the second active layer, and 
 wherein the first active layer and the second active layer include an oxide semiconductor material. 
 
     
     
       2. The display apparatus according to  claim 1 , wherein the second gate electrode is formed as one body with any one of the first source electrode or the first drain electrode. 
     
     
       3. The display apparatus according to  claim 1 , wherein the first source electrode, the first drain electrode, and the second gate electrode are manufactured by a same process using a same material. 
     
     
       4. The display apparatus according to  claim 1 , wherein the first source electrode, the first drain electrode, and the second gate electrode include a same material. 
     
     
       5. The display apparatus according to  claim 1 , wherein the second capacitor electrode is formed as one body with any one of the first source electrode or the first drain electrode. 
     
     
       6. The display apparatus according to  claim 1 , wherein the first capacitor electrode and the third capacitor electrode are connected with each other. 
     
     
       7. The display apparatus according to  claim 1 , wherein the display element includes an organic light emitting diode. 
     
     
       8. The display apparatus according to  claim 1 , wherein the second active layer is disposed to be relatively farther away than the first active layer with respect to the substrate. 
     
     
       9. The display apparatus according to  claim 1 ,
 wherein the first gate electrode, the first active layer, the first source electrode, and the first drain electrode constitute the first thin film transistor, 
 wherein the second gate electrode, the second active layer, the second source electrode, and the second drain electrode constitute the second thin film transistor, and 
 wherein an s-factor value of the second thin film transistor is larger than an s-factor value of the first thin film transistor. 
 
     
     
       10. The display apparatus according to  claim 9 , wherein the first thin film transistor includes a switching transistor, and the second thin film transistor includes a driving transistor. 
     
     
       11. The display apparatus according to  claim 1 , wherein the first active layer includes:
 a first oxide semiconductor layer on the first gate electrode; and 
 a second oxide semiconductor layer directly on the first oxide semiconductor layer. 
 
     
     
       12. The display apparatus according to  claim 11 , wherein the second active layer is formed of one oxide semiconductor layer, and
 a composition of a metal included in the second active layer is substantially identical to a composition of a metal included in the first oxide semiconductor layer of the first active layer. 
 
     
     
       13. The display apparatus according to  claim 11 , wherein the second active layer includes:
 a first oxide semiconductor layer on the second gate electrode; and 
 a second oxide semiconductor layer on the first oxide semiconductor layer, 
 wherein the second gate electrode is on the first gate electrode. 
 
     
     
       14. The display apparatus according to  claim 1 , further comprising a fourth capacitor electrode disposed on the same layer as that of the second gate electrode. 
     
     
       15. The display apparatus according to  claim 14 , wherein the fourth capacitor electrode is connected with any one of the second source electrode or the second drain electrode. 
     
     
       16. The display apparatus according to  claim 14 , wherein the first capacitor electrode is connected with the fourth capacitor electrode, and the second capacitor electrode is connected with the third capacitor electrode. 
     
     
       17. A display apparatus, comprising:
 a first gate electrode on a substrate; 
 a first active area on the first gate electrode; 
 a first source electrode on and connected with the first active layer; 
 a first drain electrode connected to the first active layer; 
 a second gate electrode on the first gate electrode; 
 a second active layer on the second gate electrode, the second active layer being spaced apart from the first active layer; 
 a second source electrode connected with the second active layer; 
 a second drain electrode on and connected to the second active layer; and 
 an organic light emitting diode connected with at least one of the second source electrode or the second drain electrode, 
 wherein the second gate electrode is integrally formed with at least one of the first source electrode or the first drain electrode, and 
 wherein the second gate electrode is at least partially on the first active layer and extends therefrom to overlap with the second active layer. 
 
     
     
       18. The display apparatus according to  claim 17 , further comprising:
 a first capacitor electrode disposed on the same layer as that of the first gate electrode; and 
 a second capacitor electrode disposed on the same layer as those of the first source electrode and the first drain electrode. 
 
     
     
       19. The display apparatus according to  claim 18 , wherein the first source electrode, the first drain electrode, the second gate electrode, and the second capacitor electrode are formed by the same process at the same time using the same material. 
     
     
       20. A display apparatus, comprising:
 a substrate; 
 a first gate electrode on the substrate; 
 a first active layer spaced apart from the first gate electrode and provided with at least a portion overlapping the first gate electrode; 
 a first source electrode and a first drain electrode connected with the first active layer respectively; 
 a second gate electrode connected with any one of the first source electrode or the first drain electrode; 
 a second active layer spaced apart from the second gate electrode and provided with at least a portion overlapping the second gate electrode; 
 a second source electrode and a second drain electrode connected with the second active layer respectively; and 
 a display element connected with any one of the second source electrode or the second drain electrode, 
 wherein the first gate electrode is disposed between the substrate and the first active layer, 
 wherein the second gate electrode is disposed between the substrate and the second active layer, 
 wherein the first active layer and the second active layer include an oxide semiconductor material, and 
 wherein the first active layer includes:
 a first oxide semiconductor layer on the first gate electrode; and 
 a second oxide semiconductor layer directly on the first oxide semiconductor layer, and 
 
 wherein the second active layer includes:
 a first oxide semiconductor layer on the second gate electrode; and 
 a second oxide semiconductor layer on the first oxide semiconductor layer, 
 wherein the second gate electrode is on the first gate electrode. 
 
 
     
     
       21. The display apparatus according to  claim 20 , wherein the second active layer is formed of one oxide semiconductor layer, and
 a composition of a metal included in the second active layer is substantially identical to a composition of a metal included in the first oxide semiconductor layer of the first active layer. 
 
     
     
       22. The display apparatus according to  claim 20 , wherein the second gate electrode is formed as one body with any one of the first source electrode or the first drain electrode. 
     
     
       23. The display apparatus according to  claim 20 , wherein the first source electrode, the first drain electrode, and the second gate electrode are manufactured by the same process using the same material. 
     
     
       24. The display apparatus according to  claim 20 , wherein the first source electrode, the first drain electrode, and the second gate electrode include the same material. 
     
     
       25. The display apparatus according to  claim 20 , wherein the display element includes an organic light emitting diode. 
     
     
       26. The display apparatus according to  claim 20 ,
 wherein the first gate electrode, the first active layer, the first source electrode, and the first drain electrode constitute the first thin film transistor, 
 wherein the second gate electrode, the second active layer, the second source electrode, and the second drain electrode constitute the second thin film transistor, and 
 wherein an s-factor value of the second thin film transistor is larger than an s-factor value of the first thin film transistor. 
 
     
     
       27. The display apparatus according to  claim 20 , wherein the first thin film transistor includes a switching transistor, and the second thin film transistor includes a driving transistor. 
     
     
       28. The display apparatus according to  claim 20 , wherein the second active layer is disposed to be relatively farther away than the first active layer with respect to the substrate.

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